1. Field of the Invention
The invention relates to a dynamoelectric method, and more particularly, to a concentrating control method of generating sets for a grid energy saving and reduction of SO2 discharge.
2. Description of the Related Art
The modern power system is a very large, vast, and complicated system; any local faults will probably cause large-area blackouts.
To maintain safety, stability, and economic operation of a large system that relates to social welfare, and the synchronous development of power systems in the grid control center, and the end of power plants, a homologous information and control system needs to be set up.
This type of system is being called “Energy Management System” (EMS). The grid control center manages and controls real-time balancing of the entire electric power system such as generation, transmission, distribution, and is supplemented by EMS.
The traditional generating set operational controlling methods based on power generating plan targets or energy-consuming indicators have evolved into methods that control the power generating set by the “sell electric price” (bid) from low to high in the control center throughout domestic and international power grids. In other words, grid control centers set the lowest cost for the purchase of electricity as a target to control the generating set. In order to adapt to changes in the power system, many grids build a separate technical support system (or grid operator control system) to adapt to the electricity market operation, on the basis of the EMS or outside the EMS, for the processing of “sold electricity” (electricity to access grid), electric price of generating set, and the corresponding control signals. Then, the EMS controls the operation of the generating set under the control commands of a grid operator control system.
Therefore, the power grid operator control system and EMS relationship between foreground and background is functional; the power grid operator control system processes the balance of power supply and demand. The grid control center uses EMS for power generation systems with real-time control under the former set of the bid and control signal of the generating set.
For the above-mentioned reasons; the world's grid control centers, to achieve market-oriented reform, adopt bidding for generating sets as the control variable to conduct real-time control on the grid generating set by EMS. Power generation enterprises must use various technical means (of which the widest used is an automatic generation control system—the main station of the plant's AGC terminal station, PLC devices, or plant stations' AGC) to control the respective set and achieve the optimizing of the allocation of resources in a single or a generating set, thus seeking to maximize economic efficiency.
In addition, both in abroad and domestic power grids, primary energy consumption of generating sets is a variable, but in many cases, coal as the representative of fossil fuel is the primary energy source. With more and more consumption of electricity in human society, coal-power generation has increased significantly. Air discharge from coal-fired power plant's flue gas such as SO2 (sulfur dioxide) and other harmful gases also will increase substantially, seriously affecting the survival of the human environment. All countries in the world are trying to reduce the total SO2 discharge in the atmosphere. With human demand for electricity growing at the same time, we need to reduce environmental pollution. For the coal-fired power plants, SO2 discharge must be reduced as much as possible.
For a single power generating set, due to restrictions on the design of fuel electricity output in certain circumstances, SO2 discharge within smoke is basically not controllable in addition to installation of desulphurization facilities. However, types of the primary energy and characteristics of SO2 discharge are not the same between different sets, and sometimes are very different. For example, for the thermal generating single set capacity of 600 MW, the output of one kilowatt of electricity consumption goes along with about 300 grams of standard coal, and for a thermal generating set with single set capacity of 50 MW, the standard coal consumption per kilowatt-hour calls for more than 450 grams, which means that in the premise of the same generating capacity and coal quality, SO2 discharge of the latter is larger than the former by 50 percent. The SO2 discharge of the same set in full-loads and low-loads are very different; hydropower and wind power generation has no SO2 discharge.
Therefore, to set the least SO2 discharge of the overall power grid as the goal is of very real social and economic significance to optimize control of the entire power grid generating set.